More precisely, the invention relates to a baseband processor comprising:                a memory to store a list of events wherein each event of said list is associated with an absolute event time field indicating at which time from the beginning of the frame processing the event should be executed,        an interface with the radio-frequency subsystem, designed to execute each event of said list of events in order to transmit to the radio-frequency subsystem the corresponding command, each event being executed during the frame processing at a time corresponding to the value of the associated absolute event time field, and        a calculator to compute and store said list of events in the memory.        
Baseband processors and radio-frequency subsystems are used, for example, in GSM (Global System for Mobile communications), GPRS (General Packet Radio Service) and EGPRS (Enhanced General Packet Radio Service) telecommunication apparatus such as cellular mobile phones to receive or transmit radio signals which are organized into frames. The structure of each frame is normalized.
In conventional mobile phones, during reception of radio signals, the radio-frequency subsystem receives radio signals, converts the radio signals into baseband signals and sends the baseband signals to the baseband processor. Thereafter the baseband processor processes the received baseband signals and controls the man/machine interfaces of the mobile phone according to the received basebands signals.
During transmission of radio signals, the baseband processor generates a baseband signal and sends it to the radio-frequency subsystem. The radio-frequency subsystem receives the generated baseband signal and converts it into a radio signal, which is sent over the air.
In order to correctly process a frame, the tuning or setting of the radio-frequency subsystem must be changed several times during the processing of one frame. For example, a frequency channel or a receiver gain of the radio-frequency subsystem must be changed while one frame id being processed. To do so, the baseband processor transmits commands to the radio-frequency subsystem at a predetermined time during the frame processing. Up to one hundred commands must be transmitted to the radio-frequency subsystem during the processing of one frame.
The time to send a command must be controlled with a time resolution as small as a one quarter-bit period. For GSM apparatuses, a one quarter-bit period is, for example, equal to 923 ns.
In order to achieve such a fine time resolution, the calculator of the baseband processor computes the list of events before the beginning of the frame processing.
During the frame processing, the interface executes this list of events so the behaviour of the interface is accurately controlled.
During each frame processing, it may be necessary to set the radio-frequency subsystem in a receiving mode, then in a transmitting mode and then back to the receiving mode. To set the radio-frequency subsystem in the receiving mode, a sequence or a succession of commands must be transmitted by the interface to the radio-frequency subsystem. The sequence of commands corresponds to a sequence of events in the list of events. Hereinafter, such a sequence of events, which corresponds to a particular change in the setting of the radio-frequency subsystem is called an operation.
Therefore, if during the processing of one frame, the radio-frequency subsystem must be switched to receiving mode two times, the list of events includes two times the same sequence of events.
To compute the list of events, a storage unit associated with the calculator stores a predefined list of events. Before each frame processing, this predetermined list of events is processed in order to cancel any unnecessary events for the next frame processing.
Because oftentimes, during the processing of one frame the same operation must be repeated two or more times, the predetermined list of events must be repeated two or more times. This repetition of operations results in an ineffective use of the storage unit space.